1. Field of the Invention
The present invention relates to negative resist composition used in a liquid-crystal display (LCD), and more specifically to negative resist composition capable of being developed with an aqueous alkaline developer solution to form a pattern into an organic insulator layer, R.G.B., a liquid crystal alignment layer, a photo spacer, or a UV overcoat of a liquid-crystal display element such as TFT-LCD.
2. Description of the Related Art
Good physical properties such as uniformity, an adhesive property, chemical resistance and toughness are required for a pattern used in an organic insulator layer, R.G.B., a liquid crystal alignment layer, a photo spacer, a UV overcoat of a liquid-crystal display element. The negative resist composition including a binder resin, a multi-functional monomer having an ethylenic unsaturated bond, and photo-initiator is preferably used as resist composition to form such a pattern, as disclosed in Korean Patent Publication No.: 10-268697.
However, a pattern formed by using the conventional negative resist compositions has insufficient ductility. That is to say, the binder resin in the negative resist composition may have an insufficient ductility in itself because it is generally composed of a ternary copolymer consisting of an acid including an unsaturated group, an acid anhydrides including the unsaturated group, or a mixture thereof; a (meth)acrylic acid derivative substituted with an epoxy group; and a (meth)acrylic acid derivative substituted with an alkyl group having 6 or less carbon atoms, or monomers having unsaturated double bonds such as cyclic alkyl ester, styrene and so on. And also the pattern may be easily brittled due to an increased cross-linking density because at least 3-valent (meth)acryl monomer is used as a multi-functional monomer having an ethylenic unsaturated bond, which may cross-link the binder resin to give chemical resistance and thermal resistance to the pattern.
As described above, the pattern formed by using the conventional negative resist composition has a disadvantage that because the pattern has insufficient ductility it is easily brittled by an external force applied in the bonding process, or by difference of a thermal expansion coefficient with a substrate caused in the hot process, thereby resulting in reduction of a manufacturing yield.